Custom barrel from scratch

The tap is a hand-tap. They do make tapping attachments for mills, but those only accommodate smaller taps, and run about $150 (plus you need a mill to use it on). A CNC mill could also be programmed to run the tap automatically, but again, you need a CNC mill for that. So, for your purposes you'll be looking at doing it by hand.

Not trying to throw more negativity at you, but it is not going to be as easy as just running the tap through a hole. Boring out close to a 1" hole, with a square shoulder on the bottom, is also going to be very difficult to do without the proper equipment.

Without going through the hassle of boring and tapping your own threads, but still being able to use threaded barrels, you might look into something like this. If you don't know, the barrel thread section on a Tippmann A-5 is actually a separate piece, that gets held into the receiver when the marker is assembled. You could use one of these, they would be very easy to modify to attach to your custom body, then you could use a standard threaded barrel. The adapters would also let you use either A-5 barrel threads, or they make them with Spyder, Cocker, and possibly other threads as well.

For those cocker threads you just need something close to 0.875" diameter before tapping, so a large 7/8" endmill plunged down the correct depth (1.24-1.25) would do it. You woudl need the endmill first though, which would run you a pretty penny for such a large thing. It's easier to produce this bore with cheaper tools on a lathe, but you'd need a lathe for that.

The tap itself will be fine operated by hand, I mean if you had the body all indexed up on a mill and you knew it was concentric to the hole you just plunge-endmilled, you could powertap it with the mill...but it would just save you like 5 minutes of elbow grease.

As told by Stobaeus...someone who had begun to learn geometry with Euclid, when he had learnt the first theorem, asked Euclid "What shall I get by learning these things?" Euclid called his slave and said "Give him threepence since he must make gain out of what he learns".

it would be really thin, although I guess you could put freak inserts into 3/4 inch pvc, it would be kind of a loose fit but an oring groove and some fort of stopper to stop it from sliding forward might work.

you could try your hand at carbon fiber. take a barrel and fill it with something like spray foam. you may have to sacrifice the barrel to get the form out. wrap the foam in a layer of packaging tape, careful not to overlap. wrap the form with carbon fiber (i dont know how strong fiberglass would be). after it sets use acetone to melt out the foam form. just take into account the thickness of the tape will enlarge bore size.

By making your own barrel you will NOT save money if thats your intention hence why 1 off parts cost more than production parts. But if I were to make a custom barrel I would use a lathe. Put a .500 drill in the tail stock and drill it through, then use a boring bar to boar the hole to say .675. I say .675 because you wont get a perfect finish and will need to leave a little material to remove by shoving a carbide ball through that is .688 or .690 or whatever size you were to buy. Doing that will result in an extremely nice finish and would apear to be micro-honed. I would do a 2 peice barrel because its very hard to get a 12 inch hole to not have tolerance deviations through out it. You could thread it on a lathe or buy a tap and die. As far as using a drill press, that would be ok for the porting but thats it. You could however use a mill that has an adjustable z axis because those are usualy really accurate if used right.

By making your own barrel you will NOT save money if thats your intention hence why 1 off parts cost more than production parts. But if I were to make a custom barrel I would use a lathe. Put a .500 drill in the tail stock and drill it through, then use a boring bar to boar the hole to say .675. I say .675 because you wont get a perfect finish and will need to leave a little material to remove by shoving a carbide ball through that is .688 or .690 or whatever size you were to buy. Doing that will result in an extremely nice finish and would apear to be micro-honed. I would do a 2 peice barrel because its very hard to get a 12 inch hole to not have tolerance deviations through out it. You could thread it on a lathe or buy a tap and die. As far as using a drill press, that would be ok for the porting but thats it. You could however use a mill that has an adjustable z axis because those are usualy really accurate if used right.

this and everything cs900 said.

but shouldn't you actually leave some extra room to further hone the barrel??? like cut to .683 (if you want .685) and then hone it .685 by a form of polishing???

sorry, not that knowledgeable.

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Originally posted by Outlawed, "She's going viral... Man the BOXXYGUN!!!"

you could get a piece of 1" pvc pipe from a hardware store. The internal dia. fits paint pretty good. Drill lots of porting in it with your drill press if you want and find a way of attatching it to your marker. TA DA, barrel made with drill press. If i get really bored i might make an entire marker out of pvc pipe, but for now this will have to do...[img width=150 height=128]http://img264.imageshack.us/img264/696/img0119qi2.th.jpg[/img]
As for a barrel with the inside dia drilled on a drill press, you could.
It would be really short and drill a hole slightly smaller than your finished dia. and hone the crap out of it with a brake hone (bottle brush) or use a reamer after you drill. Sure its doable but for the effort it takes you might be better off just getting a piece of stock with a hole already in it.

I'm going to jump in on this one, even though I'm a bit late. I have made 2 custom barrels, neither of which are very good. The first one was made by taking a 2x2in piece of aluminum, that was 12in long, and taking it to the local metal works shop. For 10 bucks, they made it a tube, .688. Took a lathe, and made some custom threads, and it worked.. but not very well. Second was the PVC pipe idea. Bought the 3/4 inch i believe, fits a paintball around .685, and made some threads on it. It looks hilarious on the field, but people get a kick out of it. It shoots, but again, not accuratly.. Have fun, and be creative.

Use a drill press for the inside and shave the outside down with a lathe then buff it out

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I look at everyone elses gun sales and I say " Damn, why don't my threads ever look like that?"
All your guys flashy colors and girls with 50 cal. amunition belts wrapped around them with their bikinis on! I realized I need bring it to the next level. I still haven't thought of how to but for now I'm clueless